Justin Quagliani, 38, died around 5 a.m., after suffering a medical emergency at his Greenwich residence while off-duty, said the Greenwich Police Department.
Police and Greenwich Emergency Medical Service personnel responded to his residence, attempted lifesaving efforts and then transported him to Greenwich Hospital where he was eventually declared dead, the department said.
A cause of death has not been determined, but there is no sign of foul play, they added.
"We wish to extend our heartfelt thoughts and prayers to the family and friends of Justin and ask the public for its support during this difficult time," the department said in a statement.
Quagliani, who joined the department in 2015, was a graduate of Stamford High School, and Phoenix University.
Before joining the department, he served as a sergeant in the U.S. Army Military Police in Iraq.
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